Ceramic lined return bend



Oct. 3, 1967 P. R. HOFFMANN CERAMIC LINED RETURN BEND Filed June 30, 1965 4 1 30h l 32 v 4 l i 3s 3 i muu. BY

MKQMM ATTORNEY United States Patent 3,344,811 CERAMIC LINED RETURN BEND Paul Raymond Hoifmann, Baton Rouge, La., assignor to Esso Research and Engineering Company, a corporation of Delaware Filed June 30, 1965, Ser. No. 468,458 7 Claims. (Cl. 138-95) This invention relates in general to tube connecting devices of the type commonly known as return headers, which are employed to connect. adjacent ends of substantially parallel tubes. for series fiow therethrough in various types of heat exchange apparatus. More particularly, the invention pertains to an improved return header for use under relatively severe operating conditions as in tubular oil stills or similar structures wherein high temperatures and high pressures prevail. Specifically,

the invention relates to an improved return header Wherein the interior surfaces subject to the most severe operating conditions may be easily and readily lined with a hard and high performance flat sheet of ceramic material which is readily available in an inexpensive and fiat form. The design of the invention permits use of ceramic materials not readily fabricated into complex curved configurations normally required.

In accordance with the invention, applicants novel return header includes a generally U-shaped body portion including a pair of spaced parallel cylindrical ports for connection as by welding to the ends of the parallel tubes. The body portion of the return header includes groove means in opposite end walls thereof for slidably receiving and securing a pair of flat ceramic inserts in substantially parallel spaced relationship. The novel header includes a cover member weldably secured to the body portion in such fashion to locate an elongated ceramic insert or inserts in tight fixed engagement against the ends of the slidable'ceramic end inserts. In this way, applicants invention has provided a novel return header employing high performance simple and inexpensively fabricated ceramic inserts which are arranged to protect the three outside walls of the header interior subject to the maximum amount of wear and heat concentration.

Accordingly, it is a principal object of this invention to provide an improved header construction employing ceramic inserts. A further object of the invention is to provide the improved return header employing fiat ceramic inserts about three walls of the header body.

A further object of the present invention is to provide an improved return header which is readily secured by welding to the associated ends of the adjacent parallel conduits.

A still further object of the present invention is to provide a return header which is simple in design, rugged in construction, economical to manufacture and has an exceedingly long service life.

These and other objects and advantages of the invention will become apparent and the invention will be fully understood from the following description and drawings in which:

FIG. 1 is a perspective view of the invention;

FIG. 2 is a vertical cross-sectional view of the return header taken generally along line 22 of FIG. 1;

FIG. 3 is a vertical cross-sectional view of the return header of FIG. 1; and

FIG. 4 is a cross-sectional view taken generally along line 44 of FIG. 3.

Referring to the drawings in particular, the invention includes a main hollow body portion 19 and a cover member 12 secured thereto by a bead weld 22. The end and side wall portions of the body define a generally U-shaped rectangular return header cavity. The body Patented Oct. 3, 1967 portion 10 includes a pair of spaced parallel formed tube connection ports 14 into which are, inserted the ends of a pair of tubes or conduits 34. The tube ends are secured by welds 36 to a beveled end portion 32 formed about the outer periphery of the ports 14.

The cover 12 is provided with a locating shoulder portion 18 which engages a correspondingly shaped recessed step portion 16 formed in the body 10. The beveled edge portions 20, 20 on the periphery of the cover 12 and the body 10 form a V-shaped groove for welding purposes. The cover 12 is made integral with the body portion 10 by a suitable Weld head 22.

Referring to FIG. 4, a pair of lips 25 formed on the interior end walls of the body define opposed spaced grooves 24 to provide a slidable track for the insertion of a ceramic end insert 26 therebetween. A welded bead 39 is provided between the lower end portions of the grooves 24 to provide a lowermost stop for each of the ceramic inserts 26. The cover When weldably attached to the body 10 is effective to tightly secure a third protective ceramic insert 28 at right angles and bridging the gap between the spaced end wall ceramic inserts 26. The thickness of the cover ceramic insert relative to the depth of the recess 16 in the body portion 10 is selected so that the ends of the insert 28 are effective to tightly secure and locate the end ceramic inserts 26 against the welds 30. In this Way, it may be seen how attachment of the cover 12 to the body portion 10 has resulted in a tight three walled ceramic lined return header of simple design. Should replacement of the ceramic inserts be required after use, the weld 22 may readily be cut and replacement of the ceramic inserts made whereupon the cover may be rewelded or replaced without need for removing the header from the ends of its associated conduits 34.

The novel design of applicants return header permits the use of standard, fiat pieces of ceramic insert materials to reduce erosion by high velocity, high temperature process streams. The straight shape of the grooves and method of installation of the insert material permits use of high performance but brittle ceramics, such as alumina type, which otherwise could not be readily used.

Thus it will be seen how applicants invention has provided a novel overall design which is simple in construction, low in cost and readily adaptable to the use of preferred, yet hard to fabricate, ceramic insert materials. The arrangement is such that the ceramic inserts are held rigidly in place by one another and by the weldably attached cover.

While a specific embodiment of the invention has been shown as described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A U-shaped return header for the interconnection of adjacent ends of a pair of spaced parallel tubes comprising opposed end and side wall means defining a main hollow body portion, and a cover portion; said body portion including a pair of spaced cylindrical ports extending through a said side wall means for receiving said tubes and an elongated oval shaped opening opposite said ports for receiving said cover portion, groove means formed in each of said end wall means of said body portion extending between each of said cylindrical ports and the adjacent end of said oval shaped opening, and first and second ceramic insert means slidably engaged respectively in each of said groove means for protecting said end wall means; means for securing said cover portion in tight sealed relationship in said oval shaped opening, and third ceramic insert means covering the inner surface of said cover portion for forming a protective surface on Ice the interior wall of said header opposite said cylindrical ports.

2. A return header in accordance With claim 1 wherein said third ceramic insert means includes end portions contacting and overlapping the ends of said first and second ceramic insert means thereby forming a substantially continuous U-shaped ceramic lining about the inside periphery of said header.

3. A return header in accordance with claim 2 wherein said body portion includes a beveled exterior edge portion 10 surrounding each of said cylindrical ports.

4. A return header in accordance with claim 3 including Welded bead means adjacent said groove means for contacting and locating the ends of each of said first and second ceramic insert means.

-5. A return header in accordance with claim 4 wherein the thickness of the end wall means of said body portion exceeds the thickness of the remainder of the wall means surrounding said ports.

6. A return header in accordance with claim 4 wherein each of said first, second and third insert means include spaced parallel fiat wall portions and are of substantially uniform and equal thickness.

7. A return header in accordance with claim 6 wherein said insert means are each of alumina.

References Cited UNITED STATES PATENTS 2,276,883 3/1942 Schon et a]. n 285--157 X 2,358,814 9/1944 Larsen 138-95 X FOREIGN PATENTS 401,870 8/ 1909 France. 740,364 5/ 1943 Germany.

LAVERNE D. GEIGER, Primary Examiner.

C. L. HOUCK, Assistant Examiner. 

